It was like this for me, too. My first try, she simply wiped the floor with me. The second, third, and fourth times I knew to kill the orbs but I could never get all of them; I'd get all but one, but I just couldn't shoot fast enough to get the last one before it healed her. So I kited her around the room in endless circles, neither of us ever losing more than a few points of health.I hated her, took me amost 30 minutes to kill her. And I survived because of the orbs, but her knockback gave her the chance to heal up full again...
I have no interupts in my build..
I knew the tactics but still didn't manage to get all the orbs killed..
But on the other hand ... nice to have such a difficult fight when I am only level 10